A: If you drive your car backwards you get better mileage.
B: Well, I tried that, but my field of view is pretty crappy in the mirror, and the controls are non intuitive.
A: Well, your shitty car design isn't my problem.
Look, whenever you're trying to change someone's behavior, you are engage in marketing. This is an important skill in the startup world.
If you told your customer "our solution is better" and he responds "your solution sets my house on fire", you DO NOT WIN POINTS by telling him that he should get a better house.
You just lost the sale.
Not only that, you made yourself look like an ass.
If you want to sell closures, and the fact that pretty much all debuggers don't make using closures easy, this is not the rest of the world's problem - it is a legitimate reason for folks NOT TO USE CLOSURES. You either have to solve it, work around it, or realize that you're not going to sell the "use closures" meme.